which reporst the error. But in this case this is not NULL-deref,note that $rbx = 2ce0ffffffffffff and this is below __PAGE_OFFSET(but above TASK_SIZE_MAX). It seems it is not even canonical. Inany case this odd value can't be valid.

Again, looks like mm->mmap pointer was corrupted. Perhaps you canre-test with the stupid patch below. But unlikely it will help. Ifmm was freed we would probably see something else.